Higher alcohols are produced, in general, by the reduction of corresponding higher fatty acid methyl esters under high temperature and high pressure conditions in an atmosphere of hydrogen.
A copper-chromium oxide-based catalyst, generally called a "copper-chromite catalyst", has been used in this type of reaction. The processes for the production of this catalyst have hardly been improved since the initial disclosure thereof in Industrial and Engineering Chemistry, vol.26, p.878 (1936). This catalyst has a serious disadvantage in that a large amount of hexavalent chromium ions are discharged in the production of the catalyst. In order to prevent environmental pollution, the heavy metals are collected by a suitable method. However, a final treatment method for heavy metal sludge produced in this method has not yet been established.
With the aim of overcoming such problem, copper-iron-aluminum catalysts produced by various processes have been proposed, for instance, in JP-A-53-92395, JP-A-55-8820 and JP-B-58-50775 (the term "JP-A" as used herein means an "unexamined published Japanese patent application", and the term "JP-B" as used herein means an "examined Japanese patent publication"). Though these catalysts are superior to the generally used copper-chromite catalyst in terms of activity, selectivity and durability, they have the disadvantage in that large scale filtration equipment is required because of their slow filtration rate when they are filtered out from catalyst-precipitated slurries during the production of a catalyst (JP-A-53-92395, JP-A-55-8820), in addition to other problems such as a filtration trouble due to considerable atomization of the catalyst when product after the hydrogen reduction is transferred from a high pressure reaction atmosphere into a normal pressure atmosphere through a high pressure valve. Also, a considerably high load is encountered upon the treatment of urea and ammonia waste water generated due to the use of urea as a catalyst precipitant (JP-A-55 -129151).